Underreamer



B. F. FEHLMAN.

UNDERHEAMER.

APPLICATION FILED JUNE 27, 1921.

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T0 alle/17mm t may concern Be it known that l", Biani-Jano F. FnirLMAN, a citizen of the lllnited States, residing at `Denver, in the county ot lenver and State vsible means `for adjustment. of the springs which act upon the outwardly projecting cutting members, and still another object is to vprovide the cutting members olf .the tool with .lapping shanks which cooperate to clean the members `from adherent mud when moved together in the operation oit the tool.

With the above'and other objects in view, all of which are fully brought out .in the course of the following description, my improved underreamer consists oi? the construction and arrangement. ot parts shown in the accompanying drawings in the. several views of which like parts are similarly designated, and in which Figure l represents an elevation ot the improved tool in its operative position in a well bore; A

Figure 2, a partially sectional fragmentary face view of the body section oli the tool showing the two cutting members thereoiz in their operative position beneath the casing of a well bore;

vFigure 3, a view similar to that ot Fig- -ure 2, showing the bits tied together inthe position they occupy when thetool is inserted in the casing;

Figure 4, a transverse section on the line 4 4, Figure 2, and

Figure 5, a similar section taken on the line 5 5, Figure 3.

Referring more specifically to the drawings, the reference character 2 designates a well bore, and 3 the protective casing thereof. The tool or' my invention comprises a bit carrying stock 4 which as usual is attached at the lower end of a drill stem through the medium of a shank 5. rlhe stock 1s composed of a body section 6 and a Specicaton'of Letters Pa tent.

Patented June 27, 1922.

i921. Serial No. @o5-1S. j

cap section T which adjoin 4each other in an axial plane and are detachably 'fastened together by means oi transverse screws, pins or bolts 8. I

rlhe contiguous faces ot the two stock sections are hollowed to provide seats 9 for the semi-spherical knuckles 10 of the bits hereinafter to be described, and in connection therewith, guide ways l2 for headed 'push bars v13 which engage in peripheral notches l0 olf the knuckles, and continuous with said ways, chambers le for coiled'springs l5 which act upon the push bars.

The axially alined guide ways and spring chambers slant toward the peripheral surface oin the stock section in which they are formed and the chambers'have at their ends threaded openings for adjusting screws 16 which engage with abutment blocks 17 inserted in the upper end portions of the springs. The headed ends 01': the adjusting screws extend in recesses 18 of the exterior surface of the stock where they are readily accessible tor the application of a. wrench, screw driver or other suitable tool.

The -bits or cutting members ot the under reamer projecting beyond the lower end of its stock, each consist of a cutting head 19 provided with a rounded cutting edge and formed integrally at the end oit a flat-faced shank 2O which terminates in the semiyspherical knuckle hereinbetore referred to. The 'knuckles ot the two cutting members are conjointly fitted in the correspondingly shaped cavities ot' the stock formed by the seats 9 of its stock sections and they are Afurther held against displacementbya pivot pin 2l which entends centrally through bores in the knuckles and therewith alined yopenings in the wall of the stock.

rlhe tlatrshanks ot the bits ylie inA lapping relation to' each other so that when the bits are moved together they will shear away the dirt whichvin the operation of the tool has lodged between the cutting members. The removal' otithis dirt iso particular value inthe operation oit a tool ot this character since its presence greatly interferes with the withdrawal of the tool through the well casing.

ln the use of my improved tool the bits are tied together by a 'ragile band 22 or other convenient means as shownfin Figure 3 of the drawings, to permit of its insertion through the casing which in wells of great kil 0 0 depth are employed to secure against the caving of their walls.

After the bits are closed together the springs are tensioned by means of the adjusting screws and the tool in this condition is lowered in the well until the cutting inembers reach the space produced beneath the casing after the latter has been slightly raised, when by rotation of the tool the fragile' band which held the bits together is broken and the bits are 'forcibly pressed against the wall of the bore under the influence of their respective springs.

The outward movement of the cutting members is limited by the engagement or shoulders formed at the juncture of their exteriorly sloping cutting heads and their shanks, with the end ot the stock and the continued rotation of the tool and simultaneous downward feed oi the same will cause the bits to ream the ground beneath the easing to a. diameter corresponding with the distance between their curved cutting edges.

The displaced earth is constantly removed from the well bore by means ordinarily employed for this purpose and after the work is completed the tool is readily removed from the well by an upward pull which causes the normally diverging heads to close together by engagement of their sloping outer surfaces with the end of the casing.

Having thus described my invention what l. claim and desire to secure by Letters- Patent is:

l. An under reamer comprising a stock having a spherical seat, outwardly projecting bits having semi-spherical knuckles conjointly litting in said seat, and springpressed means to yieldingly maintain the bits in their projecting position.

2. An under reamer comprising a stock having a spherical seat, outwardly projecting bits having semi-spherical knuckles conjointly fitting in said seat, apivot pin passing centrally through the knuckles, and spring-pressed means to yieldingly maintain the bits in their projecting position.

3. An under rcamer comprising a stock having a knuckle-seat, outwardly projecting bits having cutting heads exteriorly of the stock, knuckles conjointly litted 'in said seat and flat-faced Shanks between their knuckles and their heads, the faces of said shanks lapping in shearing relation to each other, and spring-pressed means to yieldingly {nucleic-bearing, outwardly projecting bits having knuckles conjointly fitted in said bearing, push-bars engaging with the knuckles, springs pressing on said pushbars, and adjusting-screws acting upon the springs and extending partially into the eX- te ier recesses et the stock.

fin under reamer comprising a stock composed of sections adjoiningl in a longitudinal plane and each having a circular scat, an outwardly slanting guide way connected therewith, a spring chamber continuous to the guide-way, and an exterior recess divided from the chamber by an apertured wall, bits having cutting heads projectingoutwardly from the stock and knuckles rotatably Fitted in the seats of the same, pushbars in the guide ways, engaging with the knuckles, springs in the chambers pressing on the push-bars, and adjusting screws in the recesses, extending into the chambers and acting upon the springs.

6. An under earner comprising a stock composed of sections adjoining in a longitudinal plane and each having a semispherical seat, a` guide way connected therewith and a spring-chamber continuons to the guide way, outwardly projecting bits' having notched semi-spherical knuckles in said. seats, push-bars in the guide ways, engaging in the notches of the knuckles, and springs in the chambers, acting upon the push bars.

7, An under reamer comprising an exteriorly recessed stock having a knuckle seat, outwardly projecting bits having knuckles in said seat, spring-pressed means acting upon the knuckles to yieldingly maintain the. bits in their projecting position, and adjusting screws in the exterior recesses of the stock, acting upon said means.

S. An under reamer comprising a. stock having a knuckle seat, outwardly projecting bits having knuckles in said seat, springpressed means acting upon the knuckles to yieldingly maintain the bits in their projecting position, and adjusting screws exteriorly of the stock, acting upon said means.

In testimonyv whereof l have aiiixed my signature.

BERNARD yF. FEHLMAN. 

